Sound powered telephones and method of making same



March 29, 1955 c. SCHOENEBERG 2,705,263

SOUND POWERED TELEPHONES AND METHOD OF MAKING SAME Filed April 6, 1951 ,4 22, g F|G.2. 3'2 f;

I f 30 I H I I 25 5 2/ 2 g; j my 4 X576 /7 1 FIG. I I l 7 "/j/d/ INVENTOR. CARL Sc HO E NEBERG United States Patent SOUND POWERED TELEPHONES AND METHOD OF MAKING SAME Carl Schoenebcrg, St. Louis, Mo., assignor to Jay V. Zimmerman Company, St. Louis, Mo., a corporation of Missouri Application April 6, 1951, Serial No. 219,565

1 Claim. (Cl. 179-114) This invention relates in general to certain new and useful improvements in sound powered telephones and methods for making the same.

It is the primary object of the present invention to provide a'sound powered telephone which is unusually compact and economical in construction and is highly efficient in use and operation.

It is another object of the present invention to provide a sound powered telephone which consists of a minimum of parts and therefore requires a very small amount of labor and time in assembly of its component parts.

It is a further object of the present invention to provide a sound powered telephone which is capable of transmitting sound effectively over distances in excess of one mile by electrical energy generated from the sound waves of the human voice and which, therefore, does not require any external source of power such as storage batteries, dry batteries, or an electrical generator but is nevertheless capable of providing highly satisfactory and readily audible signals over relatively substantial distances.

It is a further object of the present invention to provide a method for constructing sound powered telephones which method is simple and economical and at the same time results in a highly eflicient and precisely constructed durable product.

With the above and other objects in view, my mvention resides in the novel features of form, construction, arrangement, and combination of parts presently described and pointed out in the claim.

In the accompanying drawings Figure l is a perspective view of a sound powered telephone constructed in accordance with and embodying the present invention;

Figure 2 is a vertical sectional view taken along line 2-2 of Figure 1;

Figure 3 is an exploded view of the fixed magnet forming a part of the present invention;

Figure 4 is a side elevational view of the fixed magnet showing its parts in assembled relation;

Figure 5 is a side elevational view of the assembly ig forming a part of the present invention;

Figure 6 is a perspective view showing the component elements of the fixed magnet in assembled relation upon the assembly jig; t

Figure 7 is a vertical sectional view of the molded outer shell and assembly jig in assembled relation; and

Figure 8 is a diagrammatic view showing two sound powered telephone elements constructed in accordance with the present invention and connected together for use in a completed telephone circuit.

Referring now in more detail and by reference characters to the drawings, which illustrate a preferred embodiment of the present invention, A designates a sound powered telephone comprising an outer molded shell or casing 1 integrally including a narrow rim-like upper wall section 2, a flat bottom wall section 3, and a central or concentric socket-portion 4 having a fiat bottom wall 5. The upper wall section 2 is provided, approximately midway between its outwardly presented lip portion 6 and the bottom wall 3, with an annular shoulder 7 for supporting a disk-like thin diaphragm 8 formed of steel or any other suitable magnetic material and extending across the entire interior of the shell 1 in precisely located spaced parallel relation to the bottom wall 3.

Rigidly mounted within the socket 4 by means of a lump of hardened mastic material 9, the latter having been poured into place by a method presently to be more fully described, is a pair of L-shaped core-members 10, 11, formed of annealed steel, soft iron, or any other magnetically permeable metal, and having inwardly presented short flanges 13, 14, respectively, which are spaced endwise from each other to form a precisely measured gap 15. It should be noted in this connection that the mastic material 9 should be of such composition as will hold and support the parts of the magnet assembly firmly and securely in place but will not become brittle and crack apart under shock. Upwardly from the flanges 13, 14, the core-members 10, 11, are provided with axially aligned circular apertures 16, 17, respectively, for snugly receiving and supporting a cylindrical magnetic slug 18 formed of Alnico or other highly magnetized material. It is, of course, obvious that the slug 18 may be of square or rectangular cross-sectional shape, rather than the circular shape shown. At their upper ends the core-members 10, 11, terminate in precisely spaced parallel relation to the under face of the diaphragm 8 in the provision of a precisely measured gap 19 which is exactly one-half the width of the gap 15 when. the device is inoperative and the diaphragm 8 is stationary. In other words, the sum of the widths of the two gaps 19 between both ends of the core-members 10, 11, in the aggregate, exactly equal to the total width of the gap 15.

Snugly slip-fitted upon the upper end of the coremember 11 above the magnetic slug 18 is a dielectric tubular sleeve 20 upon which is wound a small coil 21 formed of very fine insulated wire and having a large number of turns ending in two leads 22, 23, which extend respectively through small apertures 24, 25, formed in the housing bottom wall 3 and are soldered to terminal clips 26, 27, which are, in turn, cemented or otherwise rigidly mounted upon the outer face of the housing bottom wall 3. It will, of course, be understood that two or more such coils 21 may be used either in series or in parallel and such coils 21 may be used on both coremembers 10, 11, without departing from the spirit of the present invention.

Cemented within the upper end of the shell or housing 1 is a cover-piece 28 molded preferably from the same material as the shell or housing 1 and integrally including a cylindrical wall 29 which fits snugly and telescopically within the upper wall section 2 and rests upon the peripheral margin of the diaphragm 8, being rigidly secured in such position by means of a film of suitable adhesive 30 or by a solvent-formed bond. At its upper or outer end the wall 29 integrally joins or merges into a transversely extending circular top wall 31 which is dished inwardly toward its central area in a gentle curve and is provided with an aperture 32 concentric with the socket 4 and spaced upwardly by a substantial distance from the upper face of the diaphragm 8, all as best seen in Figure 2.

The sound powered telephone A is assembled by a unique method including the use of an assembly jig B which is formed of any suitable piece of steel or other magnetic metal and integrally comprises a circular disklike body 33 which is precisely machined upon one face 34 to rest upon the shoulders 7 of the housing or shell 1. Upon such under face 34 is a raised concentric platform 35, the outwardly presented face of which is spaced from the outwardly presented face 34 by a distance precisely equal to the width of the gap 19. Centrally the disk 33 is provided with a funnel-like aperture 36 which is somewhat smaller than the distance between the coremembers 10, 11. The core-members 10, 11, are assembled as shown in Figure 4 and a small section of cardboard or other material of measured thickness is placed between the facing edges of the flanges 13, 14, so as to establish the gap 15. Thereupon, the core-magnet assembly is placed upon the disk 33 in the manner shown in Figure 6. Since the core assembly is magnetic and the disk 33 is made of steel the core assembly will become magnetically attached thereto and thus held in fixed position. With the core assembly held in such position the jig B is placed in the shell or housing 1 in the manner shown in Figure 7 and the core assembly will be thus supported in precisely fixed position. Thereupon, a suitable liquid adhesive or mastic material is poured through the aperture 36 and allowed to solidify around the component parts of the core or magnet assembly to form the retaining lump or adhesive mass 9. When the adhesive has thoroughly hardened the jig B may be removed by turning the device upside down and jarring it or by any other suitable means. Since the jig B is fairly heavy and the magnet assembly has limited magnetic strength the removal of the jig B is not particularly difficult and will not, in any way, disturb the precisely positioned relationship of the various component parts.

Thereupon, the diaphragm 8, which has been stamped by any conventional process from suitable metal is manually set in place upon the shoulders 7 and the cover-piece 28 cemented in place to form a completed telephone elementA.

Two such telephone elements A may be operatively connected together by clipping suitable lengths of conductor wire withinthe terminals 26,27, and stringing them through any intervening distance for similar connection at their other-ends to comparable terminals 26, 27, of the second telephone element A, so that the two telephone elements A are thus connected in a telephonic circuit.- When the sound of the human voice or, for that matter, any other sound impinges against the diaphragm 8, the diaphragm 8 will begin .to vibrate producing modulated variations in the gaps 19. As long as the gaps 19 are not varied in width the magnetic reluctance of the magnetic circuit established through the core-members 10, 11, will not be varied, but as soon as the gaps 19 begin to vary responsive to the movements of the diaphragm 8, the magnetic reluctance of the unit will fluctuate rapidly producing a varying flux in the coil 21 and thereby generating a fluctuating current, the fluctuations of which will be transmitted to the other coil of the companion telephone element A and induce comparable vibrations in the diaphragm 8 thereof. These vibrations will, of course, regenerate in the second telephone element A sounds identical with the sounds impinging on the diaphragm 8 of the first telephone element. Thus two persons may talk to each other by alternately speaking into one of the telephone elements A and then placing it against the ear for listening purposes when the other person carries on his portion of the conversation.

Itshould be understood that changes and modifications in the form, construction, arrangement, and combination of the several parts of the sound powered telephone and method of making same may be made and substituted for those herein shown and described without departing from the nature and principle of my invention.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

A sound powered telephone comprising a unitary molded housing integrally including a socket portion and an open-topped diametrally enlarged portion, a diaphragm mounted in and extending transversely across the enlarged portion in outwardly spaced relation to the socket, an apertured cover-plate rigidly mounted across the enlarged portion in outwardly spaced relation to the diaphragm, a magnetic element located rigidly within the socket, said magnetic element including a pair of spaced parallel L- shaped pole pieces having relatively long leg portions and short base portions disposed at right angles to the leg portions, the leg portions of said pole pieces being provided 'with circular apertures spaced upwardly from the base portions, a cylindrical highly magnetized slug snugly fitted at its ends in, and projecting through, said apertures and extending therebetween in outwardly spaced parallel relation to the base portions of the pole pieces, said magnetized slug having its oppositely presented end faces disposed in outwardly spaced relation to the adjacent lateral faces of the leg portions of said pole pieces, said pole pieces and the magnetic slug being rigidly secured within the socket in such a manner that the base portions thereof are located adjacent to the bottom of the socket and the leg portions of the pole pieces extend upwardly out of the socket into proximate relation to the diaphragm with their ends spaced from the diaphragm to provide two precisely equal gaps therebetween, said base portions of the pole pieces also being spaced endwise from each other to provide a second gap of the same width as the total width of the first named two gaps with the external ends of the highly magnetized slug presented outwardly and externally of the outer side faces of the leg portions of the pole pieces, and a wire coil wound around at least one of said members and adapted to have a variable electromotive force induced therein by variations in the magnetic flux density of the magnet element responsive to mechanical movement of the diaphragm.

References Cited in the file of this patent UNITED STATES PATENTS 1,333,004 Vaughn Mar. 9, 1920 1,402,546 Steinberger Jan. 3, 1922 1,624,338 Hanna Apr. 12, 1927 2,138,461 Sundstrom Nov. 29, 1938 2,371,819 Gustafson Mar. 20, 1945 2,400,662 Roberton May 21, 1946 2,496,483 Massa Feb. 7, 1950 2,551,447 Marquis May 1, 1951 2,559,141 Williams July 3, 1951 

